Grilli threw 25 pain-free pitches during a simulated game on Wednesday, a major step toward his return from an injury that blunted the momentum of a career year. The 36-year-old has been on the disabled list since straining the right flexor tendon in his pitching arm during a 6-5 victory over Washington on July 22.

"My arm strength is there," Grilli said. "People want to see if my arm strength is going to be there, it's there."

The righthander made the All-Star team for the first time and was second in the National League with 30 saves at the time of the injury. Grilli said he won't rush back even as the Pirates battle St. Louis and Cincinnati for the NL Central title.

"I'm going day by day," Grilli said. "Do I think I could jump in and get some outs here? Sure, but that's my confidence talking. I'm going to fine-tune things. I think everybody wants me back the way I was. So do I. Nobody is going to be more critical of me than me."

The Pirates have stayed in the thick of the playoff race with Grilli sidelined thanks to steady play by fill-in Mark Melancon, who has converted 7 of 8 save opportunities in Grilli's absence.